I have been doing a bit of random digging and found this post dated 11 Jan 2006. Unfortunately it is Dutch but my Babel Fish decoding reveals the following information.
It is due about the same time as Office Server (when ever that is!) and may be part of that family.
It consists of a server product that can do analysis and forecasting, primarily of financial data over time.
It will require Sharepoint and SQL Server but can draw data from other sources.
Business Scorecard Manager will sit within the Biz# family as its primary reporting tool.
So nothing spectacular there but it does not really sit with the other information I have which was indicating a much more loosely coupled framework for building BI solutions.
I think that the framework is where they are heading. If nothing else the code name has Dot Net connotations and that is based around a framework. However, I suspect that the scope and scale have been significantly trimmed in order to ship a product and that is why it will start as a Business Scorecard Manager Server with some extra muscle.